public class fibonacci2 {
    public static int fib(int n) {
        if (n <= 1) return n;
        else {
	    int a = fib(n-1);
	    int b = fib(n-2);
	    System.out.println(a + " + " + b);
	    return a + b;
	}
    }

    public static void main(String[] args) {
        int N = 20;
        int f = fib(N);
	System.out.println(f);
    }
}